Infusion pump devices and systems are relatively well known in the medical arts, for use in delivering or dispensing an agent, such as insulin or another prescribed medication, to a patient. A typical infusion pump includes a pump drive system which typically includes a small motor and drive train components that convert rotational motor motion to a translational displacement of a plunger (or stopper) in a reservoir that delivers medication from the reservoir to the body of a user via a fluid path created between the reservoir and the body of a user. Use of infusion pump therapy has been increasing, especially for delivering insulin for diabetics.
Continuous insulin infusion provides greater control of a diabetic's condition, and hence, control schemes are being developed that allow insulin infusion pumps to monitor and regulate a user's blood glucose level in a substantially continuous and autonomous manner, for example, overnight while the user is sleeping. Rather than continuously sampling and monitoring a user's blood glucose level, which may compromise battery life, intermittently sensed glucose data samples may be utilized for determining operating commands for the infusion pump. To achieve the desired level of accuracy and reliability and reduce the impact of noise and other spurious signals, the sensor data is filtered and calibrated using a known good blood glucose value (e.g., a fingerstick measurement). However, the filtering introduces the appearance of lag, which can degrade the user experience. Additionally, various factors can lead to transient changes in the sensor output, which may influence the accuracy of the calibration. Degradation of sensor performance over time may further compound these problems. Accordingly, it is desirable to improve accuracy and reliability while also reducing lag and improving the overall user experience.